The present invention relates to a sensor arrangement for a rotatable element.
Many rotating machines have rotatable elements for which the need for monitoring is well established. Such monitoring is needed for control purposes and/or to ensure proper and safe operation. In some cases, there is a need to monitor more than one operational parameter. For example, angular velocity is a key operational parameter, but it may be desired to monitor other operation parameters such as axial offset and/or eccentricity of rotation.
Also, in many fields, the operating conditions may be harsh, requiring sensor systems to be robust and reliable. By way of example, the petrochemical and mining industries employ many such machines that need monitoring in operating conditions that are typically harsh. An example of a rotating machine used in these industries is an electro-submersible pumps. Such pumps are usually driven by electric motors and there is existing technology for protecting the motors from overheating and detecting stall conditions using motor current.
However, there remains a need for sensor arrangements that can monitor the dynamic behavior of the pump rotation itself. Existing sensor arrangements are sometimes not ideal and typically confined to sensing of one operational parameter such as angular velocity or torque, requiring additional sensors to measure other parameters.
The present invention is concerned with the provision of an improved sensor arrangement.